Conventionally, portable sawmills have enabled the milling of relatively small logs having diameters falling within a relatively narrow range. In other words, portable sawmills have been structured and dimensioned to favor one size log or a narrow range of log sizes, and have been unequipped to be of more general utility. One example of a prior art portable sawmill is as described and illustrated by Bowman in U.S. Pat. No. 4,078,460 entitled TIMBER MILLING APPARATUS. The sawmill described therein is mounted on a wheeled, mobile platform and provides a longitudinal and a transverse carnage mounting two saw blades that are orthogonally arranged relative to one another. In order to accommodate a larger diameter log, the saw support beams are frame mounted via vertical posts that are configured to permit manual height adjustment of the saw blades above the log-centering support conveyors.
Bowman does not address how to semi-automate the process of elevating the log to an appropriate height relative to the fixed height of the saw blades, thus seriously slowing the processing of logs widely variant in diameter. Bowman also provides no means to finish-rip dimensional lumber while supporting a cant on a support mechanism. Thus, Bowman fails to address the problem of performing through cuts in a cant that is being sawn, without cutting through to the surface of the log or cant support mechanism.